Amber, green or blue bottles have been widely used for refined “sake” or for beer in order to prevent light-induced coloration, discoloration, fading in color or deterioration of the flavor of their content beverages. Those bottles are all deeply colored and thus prevent their contents from being seen as they are through the bottles. Thus, there have been needs for transparent, colorless, high-brightness glass bottles which thereby allow their contents to be seen more clearly.
In many cases, however, transparent, colorless, high-brightness glass has, at the same time, high transmittance to ultraviolet ray. Ultraviolet ray passing through a glass bottle is apt to induce coloration, discoloration or fading in color of its contents. In the case, inter alia, where refined “sake” is its content, yellowing in its color would entail deterioration of its flavor, thereby greatly impairing its commercial value. In the case of wines, too, there are problems that they would undergo coloration, fading in color and deterioration of the flavor.
As a means to solve these problems, Japanese Patent Application Publication No. S52-47812 discloses an ultraviolet ray-absorbing, colorless soda-lime glass which contains CeO2 and V2O5 as ultraviolet ray absorbents, and MnO2 or Se and, as needed, Co3O4 as decolorizing agents. This glass, however, has a substantial risk of undergoing coloration as a result of solarization because of coexisting CeO2 and V2O5. Japanese Patent No. 2528579 and Japanese Patent Application Publication No. H8-506314 disclose ultraviolet and infrared rays-absorbing glasses containing Fe2O3, FeO, CeO2 and manganese oxide. However, due to their high total iron content together with their considerable content of FeO, these glasses cannot be free of a green to blue color. This renders those glasses unsatisfactory for use in the production of colorless and transparent, high-brightness bottles that allow their contents to be seen more clearly.
Thus, there have been needs for colorless and transparent, ultraviolet ray-absorbing glass bottles which, while allowing their contents to be seen more clearly on store shelves as a result of their high transmittance to light in the visible region, enable to keep their contents from exposure to ultraviolet ray in the process of distribution and on store shelves.
In order to meat the needs, the present inventors previously found that an ultraviolet ray-absorbing, colorless and transparent soda-lime-silica glass that is highly absorptive of ultraviolet ray while having high transmittance to visible light, is obtained by adding predetermined proportions of SO3, cerium oxide, Fe2O3, FeO, manganese oxide and, as needed, cobalt oxide to a conventional basic composition of soda-lime-silica glass, and filed on the basis of the findings an international application PCT/JP99/04564 (WO 00/12441). However, there are still needs for glass bottles that allow for further reduction in transmittance to ultraviolet ray, while remaining colorless and transparent.
The objective of the present invention is to provide an ultraviolet ray-absorbing, colorless and transparent soda-lime-silica glass and glass bottles made thereof which, while maintaining high transmittance to light in the visible region and thereby allowing their contents to be seen more clearly, absorb more ultraviolet ray and thereby serve to prevent ultraviolet ray-induced coloration, discoloration, fading in color or deterioration of the flavor of their contents.